Aspirator burner



May 12, 1964 n. MEYER ASPIRATOR BURNER 3 Sheets-Sheet 1 Filed June 7, 1960 FIG.2

'IZEIIIIIIII INVENTOR. DAV/D ME YER Z M% W ATTORNEYS May 12, 1964 MEYER 3,132,683

ASPIRATOR BURNER Filed June 7, 1960 3 Sheets-Sheet 2 FIG.4

, INVENTOR.

DAVID MEYER l ve. 5

A T TORNE YS May 12, 1964 D. MEYER 3,132,683

ASPIRATOR BURNER Filed June 7, 1960 3 SH e'ets-Sheet 3 FIG. 8

INVENTOR.

4l2 DAVID MEYER I} WM,W+W

ATTORNEY$ A quired in a pressurized primary air system.

manufacturing costs;

United States Patent 3,132,683 ASPRATOR BURNER David Meyer, Canton, Ohio, assignor to E. W. Bliss Company Filed June 7, 1960, Ser. No. 34,523 7 Claims. (Cl. 15828) The present invention is concerned generally with burners for fluid fuels such as gases or oils, and more particularly with fluid fuel burners of the type which are supplied with air under pressure and are adapted to project the burner flame into a furnace or other combustion space.

A burner constructed according tothe present invention comprises a refractory combustion tube having at one end a centrally located main air inlet orifice supplied with air under pressure and a fuel inlet nozzle disposed in the orifice coaxial aligned with the combustion tube. The opposite or front end of the burner, that is the outlet end, is circumferentially flanged or enlarged to form a protector wall into which the combustion tube interior suddenly expands to form a burner mouth, and which protects the burner from heat reflected'out of the chamber being fired. Further the burner is provided with secondary air and tertiary air chambers circumferentially disposed about opposite ends of the combustion tube, which have adjustable air intake openings and communicate through circumferentially spaced series of air passages or inlets respectively radially with the combustion tube space just forward of the primary air orifice and axially through the tube flange with the burner mouth. The enlargement at the mouth end of the burner also serves in conjunction with the associated tertiary air chamber as part of a sound muflling arrangement, while the expanded mouth itself functions both to induce air into the burner from the tertiary air chamber and to provided a primary air chamber having centrally apertured opposite walls respectively mounting a primary air orifice member and a fuel nozzle which forms a relatively large annular air space about the entrance to the primary air orifice, the chamber being supplied with air under pressure from a blower system. This arrangement as hereinafter described in detail provides first an aspirator type action whereby air is drawn into the burner from the free atmosphere through the secondary and tertiary air inlets.

The introduction of the air and fuel tothe combustion tube at the primary air orifice region provides a thorough mixing of air and fuel as well as tending to induce the additional secondary air through the circumferentially spaced series of secondary air inlets. A resulting high flame velocity occuring in what appears to bea. continuous series of extremely rapid explositions results in the induction of further air from the atmosphere through the tertiary air supply inlets, along with'a further thorough admixing of this additional air. Among other features the thorough mixing of air and fuel attains a higher than usual burner efficiency and flame temperature. I The aspirator action in bringing in further additional secondary and tertiary air thereby reduces the blower capacityre- Further in the specific construction hereinafter described, the burner is interchangeable or adapted foruse of either oil or gas or dual (i.e'. joint) firing of oil andigas as the fuel without any material loss of efficie'ncy bya simple exchange of fuel nozzles; 'Also the general construction is rugged though simple and of relativelylow It is the general object of the present invention to pro- 3,132,683 Patented May 12, 1 964 ,"rce

-vide aburner of the character described of'higher operating efficiency and flame temperatures. Another object of the present invention is to provide an aspirator type burner supplied with primary pressurized air which'in duces supplemental air through secondary and tertiary air inlets from the free atmosphere; A further object 7 of the present invention is to provide an efficient burner adapted to use of simplified controls for operation. A still further object is the provision of a burner of the character described which is readily convertible from one type of firing to another. A still further and more specific object is to provide a burner wherein a hgih degree of mixing of the fuel and the required air is attained.

Other objects and advantages will appear from the following description and the drawings wherein:

FIG. 1 is a longitudinal section taken vertically through the axis of a burner unit according to this invention;

FIG. 2 is a back or outer end' view of the burner taken from the left end ofFIG. l in the drawings;

FIG. 3 is a fragmentary view taken as indicatedby the section line 3-3:in FIG. 1, showing the structure of 'a secondary air control shutter; 1..

FIG. 4 is a detailed sectional view of the secondary air Iaggro; shutterxtaken as indicated by the line 44 in FIG. 5 is a fragmentary longitudinal section showing details of a primary air orifice memberof .the burner, and also disclosing an oil fuel injector nozzle substituted for the gas fuel nozzle of FIG. 1; i

FIG. 6 is a vertical longitudinal section through the primary airchamber of annit having a fuel nozzle modification adapted to dual firing; with a suitable variation in surrounding primary air chamber to accommodate the andoil nozzle interchangeable with that nozzle in FIG. 6; an

FIG.'8' si1nilarl-y shows a with that of FIG. 6. a

For convenience, in the following description the'right end of the burner as it appears in FIG. 1 will be termed the inner or front end of the burner. In the following description of the invention, basically three species 'are discussed in which like but notiden'tical parts are referred to for purposes of illustration.- A descriptiono f the parts and functionsof one species will rendef understandable by those skilled in the art parts of the other species, although not necessarily specifically-referred to. Like parts of the species shown in FIGURE 5 are distinguished from corresponding parts .of the species of FIGURE 1 by resorting to numerical identification in the IOQ series; Like parts of-the species shown in FIGURE 6 are distinguished fromthe species shown in'FIGURES' 1 and 5 by numerical identification in the 200? series. V in FIGURES 7 and 8 are identfied by the 300 and 400 series respectively. Thus,a part 12 of FIGURE 1, has a like part 112 in FIGURE 5, a like part 212 in -FIGURE '6', a like part 312 in'FIGURE 7, and a me part 412111 As seen in FIG; 1', the .burner of this invention-cornprises as principallfunctio'nal components (designated by general reference numerals) the combustion tube a primary ,or pressurized airi supply chamber 11; a fuel nozzle module assembly 12' and a primaryfair orifice member 13 supported by the 'air s'up'pjly chamber struck .ture in coaxial alignment with each other'and w'ith the combustion tube 10; an annular secondary air supply chamber extending circumferentially aboilt the rear eiid of the combustion tube and communicating with-'the-interior of the latter'through ,a circumferentially spaced series (here eight) of radial secondary air inlet passages gas nozzle interchangeable the corresponding Like parts in sub-assen'rbly shown" end of the burner in a desirable size range.

15; and an annular tertiary air supply chamber communicating through a circumferentially spaced series of longitudinally directed tertiary air inlet apertures 17 (here eight) with the peripheral region of the radially expanded shallow mouth space 18a of the combustion tube interior space 18. Generally a series of small apertures 17 is preferred to aid in reducing the operating noise level of the burner, and also to keep the diameter of the mouth Although the number of these apertures may vary according to their size and that of the burner, the total cross-sectionalv area thereof should be about that of the primary air inlet to chamber 11 in a burner unit as shown.

14a, 16a for air intake openings thereof as hereinafter described.

In the specific form of the burner disclosed in the drawings, a cylindrical metal member 26, a centrally apertured therein as a lining, and may be considered to form av housing for the burner unit. A bracket or pedestal 25 is secured to the bottom of the shell portion 20 for mounting the burner securely or rigidly in its environment of use, before an opening of a combustion space into which the burner fiame is projected. For the lining material 24 providing the functionally effective combustion tube structure, among prior art .expedients, a lining having composition and manner of formation described in my issued Patent 2,646,376 is preferred.

The chambers 14 and 16 have similar shutter type adjustments It will be noted in FIG. 1 that the combustion tube block has a centrally apertured back end wall into which the orifice member extends; and that the circumferentially spaced series of radial secondary air inlet passages 15 open into the interior of the tube just forward of the wall. The interior space 18 of the combustion tube has a slight divergent taper toward its front end until it meets a sudden expansion into a short cylindrical section 1811 in the radially flanged or enlarged end portion of the refractory tube forming the burner mouth.

The primary air supply. chamber 11 may conveniently be fabricated as a cast metal member, the body 28 of which in front elevation is of generally round form (see FIG. 2) and is bolted at lugs 29 to the casing end plate 21. Integral with the body is an upwardly extending "broad air inlet portion 30, here shown as having a bolt ,flange for connection to air piping, although obviously an internal pipe thread could be used therein. The front and back walls 31, 32 connected by theshort cylindrical peripheral orvside wall 33 are centrally thickened and apertured for reception and mounting respectively of the orifice member 13 and fuelnozzle assembly 12, the aperture of wall 32 being large enough to permit introduction andremoval of member 13.

. The primary air supply chamber llprovides a'relafrom FIG. 5, the orifice member 113 is of a short generally cylindrical external form with a slight circumferential rib 137 at its back end and is received in a correspondingly machined centrally apertured thickened part 131a .of the back wall, to which it is clamped in position in fixed, relation by overhanging clip plates or clamping lugs 138 secured by bolts 13. The cylindrical bore of the orifice member 113 terminates at a sharply tapered or convergent portion 113a-forming a narrowed circular opening which in conjunction with the front end of the tively large annular air flow space entirely around the inlet to the air orifice member 13. As may'bestbe seen whereby the entire assembly is mounted to the outer Wall member 111. I

The circumferential annular secondary air supply chamber 14 (see FIG. 1), formed by the radially projecting portion of plate 21, member 44 and radial wall member 45, has a circumfereutially spaced series of elongated arcuate slots 46 in member 45 as secondary air intake openings. The area of the air intake apertures 46 should be at least as great as the flow area of the inlet passages.

15. For adjustment of the elfective air intake openings (see also FIGS. 3 and 4), an annular disk shutter (here shown as formed of members 48, 49, bolted together at opposed end flanges 50), provided with a corresponding series of arcuate elongated slots 51, is held in rotatably adjustable relation against the outer face of wall 45 by overhanging clips or plates 53 bolted at 54 to angle brackets secured to the outer wall 44 of the secondaryair chamber structure. Each plate 53 has an. elongated arcuate slot 55 for reception of a respective stud 56 projecting from the shutter disk for clamping by a clamp nut 57 on the stud. The tertiary air supply chamber formed by members 22 and 23 and a rearwall member 59, again having a circumferentially spaced series of air intake apertures 60, has an adjustable shutter structure 16a for controlling the effective size of the aperture. 69 similar in form to that just described for the secondary air chamber. Since so great an air intake is not required at this .point, simple apertures rather than slots suifice, however.

For gaseous fuels, the fuel nozzle assembly 12 consists of a tube 12a which is (see FIG. 1) received through a central aperture in base plate 12b and has a, threaded enlarged outer end for a connection to the fuel supply piping, the tube being held in position by set screws 62 .threadedthrough the outward boss 63 on the base plate.

For fuel oil (see FIG. 5) the nozzle tube 112:: assumes the form of an atomizing nozzle having one end threaded into a boss 65' and in communication with the internal pipe threaded external aperture 66v of the base 112]) whereby a connection to the fuel oil supply line is made. The nozzle tube has an enlarged portion 67 suitably formed for engagement by a wrench or other tool for removal or application ofthe tube inthe assembly. .The circumferential flangeod at the front end of the oil nozzle, has a series of spaced apertures 69, the outer face of which flange is disposed substantially flush with or in the plane of the end of the orifice member 113. The fuel oil channel 70 opens to the exterior at the inner periphery of flange 68 through a series of obliquely directed atomizing jet. apertures. 71 corresponding in number. and position andcentered with respect to the respective apertures .69.

In FIG. 6 the fuel nozzle-assembly 212 is adapted to dualfiring, i.e., simultaneous firing, of both gas and oil as fuels. Reference numerals or characters in FIG. 6

also in FIGS. 7 and 8) similar to those of the previously :described structures indicatev analagous parts.

Theprimary :air chamber 211 with the primary air inlet 30 threaded for a pipeconnection and the primary airori- .fic'e element 213 held in or on the primary air. chamber gas inlet arm 83 threaded at .83a,for connectionto the gas supply. Projecting into the interior space of the housing 211 is a short cylindrical extension 84 formed'in the front wall of body .80, coaxially aligned with orifice member 213, upon which is .fitted and secured by a set screw 85 thebroad funnel-likebase of a gas nozzle sleeve 86 having a cylindrical portion of reduced diameter 86a,

extending partially into the orifice member 213 to direct through the latter gas issuing through the circumferentially spaced series of apertures 84a from the hollow interior of the housing 80.

An axial fuel oil tube 88 has a passage 87 extending 7 through the back wall of the housing 80. The fuel oil tube 88 and the front wall portion or cylindrical portion 84 in internally threaded at its back end for connection to oil supply piping and at its front end for securement opening at 213b and, in issuing around and, through respectively the flange 68 and its apertures 69, will be jointly effective in securing an introduction of oil to the burne in atomized form.

In FIG. 7 a nozzle assembly 312 suitable for oil firing and adapted for substitution in the environment of FIG. 6 is disclosed, which is essentially the same as that previously described for FIG. 5. There has also been substituted in the environmentof FIG. 6 an orifice member of arrangement and shape similar to that of FIG. 5 relative to the flange 68. The gas nozzle assembly of FIG. 8 again is essentially similar to that of FIG. 1 and adapted to the environment of FIG. 6 having an orifice member 413 similar to that of FIG. 7. g i

The structure common to the three types of fuel nozzle assemblies as above described permits a simple substitution of one type of fuel nozzle for the other when a in the drawing with a total secondary air inlet area of 3.976 square inches; a primary inlet orifice with a diameter of 1. inch providing an annular orifice area of .4049 square inch about the gas tube 12a. This burner is adapted to handle natural gas supplied under 1 to 3 p.s.i. pressures at a gas flow rate of from 500 cubic feet to 1,080 cubic feet of gasper hour for natural gas having heating values of from 1000 to 1050 B.t.u. per cubic foot, with air supplied at pressures of 1 to 3 p.s.i. at flow rate of 2,700 to 5,400 cubic feet per hour (gas volumes reduced to standard conditions). About an equal total volume of additional air is supplied in about equal amounts through the secondary and tertiary air inlets. The efficiency of combustion attainable at the burner ran from 95 to 98 percent total combustion, with a heat release of from 500,000 to 1,080,000 B.t.u. per hour.

I claim:

1. A fluid fuel burner adapted to fire into a furnace or like space comprising: a refractory lined combustion tube having at one end a wall with a central aperture for introduction of air and fuel and a flange means at the other end of said tube having refractory lined outwardly and forwardly extending portions forming a radially expanded forwardly open shallow mouth space, said tube opening through said mouth space, a primary air chamber structure adapted for connection to a source of pressurized air and opening through said aperture to discharge a primary air supply into said refractory lined combustion tube; and a fluid fuel nozzle supported by said primary air chamber structure in axial alignment with said refractory lined combustion tube to discharge fuel through said aperture into the interior of said refractory lined tube; said refractory lined tube having a plurality. of lateral circumferentially spaced secondary air intake passages adapted to admit atmospheric air and directed inwardly through said tube in front of said wall; and said flange means having a plurality of circumferentially spaced tertiary inlet passages adapted to admit atmospheric air and extending forwardly through said outwardly extending portion through said flange means into said radially expanded shallow mouth space.

2. A fluid fuel burner adapted to fire into a furnace or like space comprising: a refractory lined combustion tube having a centrally apertured wall at one end and a flange means at the other end of said tube having refractory lined outwardly and forwardly extending portions forming a radially expanded forwardly open shallow mouth space, said 'tube opening through said mouth space, a primary air orifice member mounted in the aperture of said wall; a primary air chamber structure adapted for connection to a source of pressurized air and connected to said wall' to enclose said orifice member and discharge a primary air supply into said combustiontube in a generally axial direction; a fluid fuel nozzle supported by said primary air chamber structure in axial alignment with said combustion tube to discharge fuel through said orifice member into the interior of said combustion tube; a secondary air supply chamber means disposed circumferentially of said combustion tube adjacent 'said Wall and having a plurality of secondary air intake passages axially directed toward the interior of said secondary air supply chamber, said secondary air supply chamber communicating with said combustion tube by means of passageways through the refractory lined combustion tube for directing secondary air across the mouth of said fluid fuel nozzle; a tertiary air supply chamber means disposed circumferentially of said combustion tube adjacent said radially expanded shallow mouth space and having a plurality of circumferentially-spaced tertiary air intake passages axially directed into said tertiary air supply chamber, and said refractory lining having openings therethrough to provide passageways from said tertiary air supply chamber to said radially expanded shallow mouth space.

3. A fluid fuel burner adapted tofire into a furnace or like space comprising: a refractory linedcombustion tube having a centrally apertured Wall at one end and a flange means at the other end of said tube having refractory lined outwardly and forwardly extending portions forming a radially expanded forwardly open shallow mouth space, said tube opening through said mouth space, -a primary. air orifice member mounted in the aperture of said wall; a primary air chamber structure adapted for connection to a source of pressurized air and having a toroidal configuration concentric with and enclosing said primary air orifice member to discharge a primary air supply into said combustion tube in a general axial direction; a fluid fuel nozzle supported by said primary.

air chamber structure axial alignment with said combustion tube to discharge fuel through said orifice member into the interior of said combustion tube; a secondary air supply chamber means, and a tertiary air supply chamber means, each disposed circumferentially of said combustion tube, and each including intake apertures adapted to admit atmospheric air, said combustion tube having said secondary and tertiary air supply air inlet a flange means atthe other end of said tube having refractory lined outwardly and forwardly extending portions forming a radially expanded forwardly open shalsaid wall'to enclose said orifice member to provide cornmunication between said primary air chamber structure and said refractory lined combustion tube; a fluid fuel nozzle supported bysaid primary air chamber structure in axial alignment with said combustion tube to discharge fiuel through'said orificemember into thein- ,terior of said combustion tube; a secondary airsupply ohamber means, and a tertiary air supply chambermeans air'palssages are adapted to admit'supplementa-l atmoseach disposed circumferential-11y of said tube and each having atmospheric air intake apertures; said combustion tube having-a plurality of radially directed secondary passages immediately adjacent said wall communicating with said secondary chamber means for directing streams vof air past the mouth of said fluid fuel nozzle, said flange meanshaving a plurality of axially directed circumferentially spaced tertiary apertures communicating said tertiary chamber means with said radially expanded shallow mouth space, the respective areas of said secondary passages and said tertiary apertures being approximately equal, and the combined areas of said secondary pasjsages and said tertiary apertures being adapted toadrnit supplemental atmospheric air approximately equal in volume to the primary air admitted through said primary air chamber structure. 7 p a ,5. A fluid fuel burneradapted to fire into afurnace orlike space comprising: a refractory lined combustion tube having a centrally apertured wall at one end and an outwardly extending flange at the other end; a flange means at the other end of said tube having refractory lined ouwardly and forwardly extending portions forming a radially expanded forwardly open shallow mouth space, said tube opening throughsaid mouth space, a

wall of said tube; a primary air chamber structure adapted for connection to a source of pressurized and opening through said orifice for discharging a'primaryair supply into said combustion tube in a generallyaxial direction; fluid fuel supply means supported-by said primary air chamber structureuin alignment with said tube to discharge fuel through-said orifice'member into the interiorof said combustion tube; and secondary. airsupprimary air orifice member extending: into theapertured i of air supply passageways extending therethrough in front of said apertirred Wall communicating said secondair supply meanswiththe interior of said tube, said flange means having a plurality of circumferentially spaced tertiary supply passageways extendingdorwardly through said outwardly extending portion of said flange means into said radially expanded shallow mouth space;

6.' A burneras described in claim 1 wherein the total flow areas of said secondary and said tertiary passages are approximately equal and said secondary and tertiary pheric air approximately equal :in :volnmeto primary 7. A'burrie r as described in claim 1, for dual firing of gaseous and liquid rues, wherein said primary air chamber structure includes front and back wallshaving aligned central ,aperturesrsaid orifice'member being secured at the front wall aperture; theiapeifture of the back :wall ibeing relatively danger for access to and replacement of said orifice member and wherein said fuel supply means comprises a gas supply chamber secured to the back wall of the primary air chamber and closing the aperture thereof, said gas chamber having an external connectionto a gas supply; a -firel oil tube extending through said gas supply chamber in axial alignment with said combustion tube through saidprimary air chamber and-into said orifice member and having an external supply connection; said fuel oil tube havingiaplurally ape-rtured flange in circumferentially spaced relation to the outlet end of said orifice member iand oblique atomizin g pas sages opening in horn of respective flange apertures, and a gas nozzle sleeve supponted by and extending from said gas supply chamber within said primary air chamber in coaxial relation, to said fuel oil tube; said gas supply chamber opening into said nozzle sleeves.

' References Cited in the file of this patent v i V -'UNITED STATES PATENTS 1,063,352 Jacobs Ju.ne3, 1913 1,069,243 Folger AugQS, 1913 1,172,755 Wilson J. Feb. 22, 1916 '1,s17,47o Adm Augf4, 1931 l,84l1,69'8 i Barber Jan. 19, 1932 2,621,477 1 Powter et al'.. Decsl6, 1952 2,775,293" Raymond et alf Dec. 25, 1956 2,844,140 Wein a July 22, 1958 2,952,307 7 S'chrarnm et t. Sept. 13,1960 1 2,964,103 7 Ryder Dec. 13,l96O

I. a i E 1 FOREIGN PATENTS V i 185,479 Austria l Au;g. 15; 1955 Switzerland July 16, 1941 

1. A FLUID FUEL BURNER ADAPTED TO FIRE INTO A FURNACE OR LIKE SPACE COMPRISING: A REFRACTORY LINED COMBUSTION TUBE HAVING AT ONE END A WALL WITH A CENTRAL APERTURE FOR INTRODUCTION OF AIR AND FUEL AND A FLANGE MEANS AT THE OTHER END OF SAID TUBE HAVING REFRACTORY LINED OUTWARDLY AND FORWARDLY EXTENDING PORTIONS FORMING A RADIALLY EXPANDED FORWARDLY OPEN SHALLOW MOUTH SPACE, SAID TUBE OPENING THROUGH SAID MOUTH SPACE, A PRIMARY AIR CHAMBER STRUCTURE ADAPTED FOR CONNECTION TO A SOURCE OF PRESSURIZED AIR AND OPENING THROUGH SAID APERTURE TO DISCHARGE A PRIMARY AIR SUPPLY INTO SAID REFRACTORY LINED COMBUSTION TUBE; AND A FLUID FUEL NOZZLE SUPPORTED BY SAID PRIMARY AIR CHAMBER STRUCTURE IN AXIAL ALIGNMENT WITH SAID REFRACTORY LINED COMBUSTION TUBE TO DISCHARGE FUEL THROUGH SAID APERTURE INTO THE INTERIOR OF SAID REFRACTORY LINED TUBE; SAID REFRACTORY LINED TUBE HAVING A PLURALITY OF 